Ten Random Astro-Facts to Entertain and Boggle

From a Flammarion woodcut, unknown artist.

I decided that instead of blogging on just one topic in astronomy, I'd blog about ten of them! Here are some of the astronomy fun facts from my archive that struck my fancy today, randomly chosen and in no particular order:

1. In the city we can see maybe a few dozen stars on a "dark” night—still, there are about 2000 stars overhead that are within our eye's ability to see, if only the skies were darker! The total number of individual stars perceptible by the human eye, in all directions in space, is around 6000, give or take depending on how good your eyesight and night vision are.

2. In terms of size, the Earth is over 6 million times larger than a human being; compared to a typical atom, a human is over 20 billion times larger! Our personal scale in the universe is a lot closer that of even the vast Earth we live on than to the atoms that make us!

3. The largest known star, the red supergiant NML Cygni, is approximately 1650 times the diameter of our sun, or over 1.4 billion miles across! Placed where our sun is, this star would swallow up all the planets closer to the sun than Saturn—and Saturn itself would practically skim the star's surface!

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4. In about 5 billion years a day on Earth will be 48 hours long and the sun will start to run out of fuel. So, yes, we live on a planet orbiting a star, both of which are slowly winding down.

5. Television transmissions from the earliest TV broadcasts have traveled over70 light years into spaceand have passed through over 500 star systems, many with known planets. I Love Lucy original broadcasts are at this moment reaching other planets!

6. There is roughly the same number of stars in the universe as water molecules in a drop of water.This kind of fact always turns my attention away from how big the universe is to how ridiculously small its constituent parts are.

7. The old Greek word for "comet” is "disaster”. It means literally "bad star.” Many cultures regarded the appearance of a comet in the skies a bad omen or harbinger of doom.Have you seen a disaster lately?

8. The moon may be 400 times smaller than the sun, but since it's 400 times closer to us they appear exactly the same size! What a coincidence. Since the moon was once much closer to Earth, and will in the future get much farther away (at a rate of mere inches per year), it is a bit of a coincidence, really. But, of course, it was bound to pass through this state at some point, and the only real coincidence is that we are alive at present to remark on it.

9. The most distant object in the Universe perceivable to the unaided human eye is theAndromeda Galaxy, about 2.5 million light years away! That's 15 billion billion miles! Everything else we can see without a telescope is a lot closer to us!

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10. Imagine taking the entire Earth and everything in it and crushing it to a mere point in space, infinitely smaller than a grain of sand. This idea may be beyond imagination, but it's not beyond nature. Black holes are points in space where the mass of entire stars, and even millions or billions of stars, has collapsed. Kind of makes one re-think what solid matter actually means.

And the list goes on. What a privilege to exist in a reality where such mind-boggling facts absolutely abound!